Aside from taming breakouts, antibiotics can help limit consequences like permanent scarring, which occurs in about 20% of all people living with severe acne. While effective, these drugs have side effects that should be considered.
This article details the antibiotics commonly used to treat acne and how they work. It presents information about side effects, as well as the growing problem of antibiotic resistance that may affect how and when they’re prescribed.
How Antibiotics Work on Acne
Antibiotics work by several mechanisms. The most important one is the decrease in the number of acne-related bacteria in and around the hair follicle.
Specifically, the follicle becomes obstructed and an overgrowth of normal skin bacteria destroys the lining of the follicle. As a result, the bacteria and debris enter the dermis layer of the skin, causing an inflammatory response.
Antibiotics also work by reducing the irritating chemicals produced by white blood cells. Finally, antibiotics reduce the concentration of free fatty acids in the sebum, also reducing the inflammatory response.
How Long Does It Take For Antibiotics to Clear Acne?
Generally speaking, expect to use antibiotics for three to four months before you notice significant acne improvement. The recommended course will, however, differ depending on the medication used and your skin.
Some people may take an antibiotic for much longer, with one study of amoxicillin reporting an average duration of 37 weeks. Your dermatologist will ensure they’re prescribing safe and effective treatment.
Tetracycline
Tetracycline was once the most widely prescribed class of antibiotic for acne, but it’s the tetracycline derivatives like doxycycline and minocycline that are more commonly used today.
There are several antibiotics within the entire class, including tetracycline, which remains available in both 500-milligram (mg) and 250-mg formulations.
The usual starting dose is 500 mg twice a day continued until a significant decrease in acne lesions is seen. The dose can then be decreased to 250 mg twice a day or discontinued.
Tetracycline may cause stomach upset. Eating it with non-dairy foods is often advised, as dairy products decrease absorbtion and render it less effective.
Minocycline
Minocin (minocycline) is a tetracycline derivative that has been used effectively for decades as a treatment for acne. It is especially useful for pustular type acne. A pustule is a pus-containing vesicle such as a whitehead surrounded by redness.
While the absorption of minocycline is decreased with food, it is not as significant as the decrease seen with tetracycline. The usual starting dose is 50 to 100 mg twice a day.
Minocycline (and theoretically any tetracycline derivative) should be avoided in those who are using Accutane (isotretinoin) as the combination of these may result in a condition in which there is increased pressure within the skull (pseudotumor cerebri).
Doxycycline
Doxycycline is often used for people who do not respond to or cannot tolerate erythromycin or tetracycline, or for those who will likely have difficulty with the “no food” guidelines of some drugs.
The dosage of doxycycline is started at 50 mg to 100 mg twice a day. It should be taken with food; otherwise, it can cause significant nausea.
Doxycycline is more likely than tetracycline to increase sensitivity to the sun or cause sunburns, a phenomenon known as photosensitivity. There are other acne medications that may cause photosensitivity as well, such as benzoyl peroxide, alpha-hydroxy acids, and topical retinoids.
Doxycycline is available under these brand names: Doryx, Oracea, Monodox, Atridox, Morgidox, Vibra-Tabs, Alodox, Ocudox, Doxy, Acticlate, and Vibramycin.
Amoxicillin
Amoxicillin is not considered a first-line drug for treating acne. However, a study of 26 people who were first treated with other antibiotics without success found that 85% of them saw improvement with amoxicillin when used alongside topical treatments and/or hormone therapy.
Amoxicillin for acne has certain advantages. High among them is that it is safe for use in pregnant people. It can be used when drugs in the tetracycline class aren’t an option.
It typically has fewer side effects, though nausea, diarrhea, and headache can occur.
Amoxicillin for acne also may be a good option for people with allergies to doxycycline and other first-line drugs. A daily dose of 1000 mg, or in more serious cases 1500 mg, appears to work well.
In the United States, amoxicillin is sold under brand names including:
AmoxicotAmoxilDisperMoxMoxilinTrimox
However, because it’s in the penicillin class of antibiotics, it can’t be used in people with penicillin allergies or, in some cases, those diagnosed with certain health conditions. Tell your healthcare provider about these conditions, which include:
Kidney diseaseAsthmaHay feverMononucleosis
Septra/Bactrim and Macrolides
Septra or Bactrim (sulfamethoxazole/trimethoprim) and Zithromax (azithromycin) a macrolide, have often been used to treat moderate to severe inflammatory acne.
Studies do not seem to favor one antibiotic over another with this condition, but treatment appears to work much better when combined with topical therapy.
Topical Antibiotics
Clindamycin is most widely prescribed as a topical antibiotic. The starting dose is 75 to 150 mg twice a day.
The major side effect of oral clindamycin therapy (which is rarely used anymore) is a serious intestinal infection called pseudomembranous colitis caused by the bacteria, Clostridioides difficile (C. difficile or C. diff).
A C. difficile infection is much more common with oral clindamycin but has been reported with the topical product as well.
Topical clindamycin is available as Cleocin-T, Clinda-Derm, Clindagel, Clindets, C/T/S, and Evoclin.
Antibiotic Side Effects
All antibiotics can cause vaginal yeast infections. Tetracycline seems to be the antibiotic that most frequently has this side effect.
All oral antibiotics can also lessen the effectiveness of birth control pills, so those who are taking these antibiotics should use a backup birth control method. Nausea is fairly common with erythromycin and doxycycline.
Concerns About Antibiotic Resistance
In recent years, healthcare professionals have been seeing increasing resistance of the bacteria Propionibacterium acnes against the oral antibiotics used.
Current strategies to reduce resistance recommend using antibiotics in combination with topical treatments and limiting the duration of use when possible. This, however, has impacted the overall effect of antibiotics on acne.
As is the case with prescribing any medication, the risks have to be weighed against the rewards. Discuss all of your options with your healthcare provider.
While short-term use of antibiotics is generally considered best, not finishing a recommended course of one of these drugs can actually contribute to the problem of antibiotic resistance.
A Word From Verywell
Antibiotics can be very helpful for some people with acne and work by a combination of mechanisms. Some antibiotics work better for particular types of acne and your dermatologist can make the best choice by understanding your history of acne as well as your lifestyle.
As with any medications, side effects may occur. Fortunately, there are several different choices available if one of the above is not helpful. Antibiotics are usually used in combination with topical treatments and good daily skin care for acne-prone skin.
